1. Field of the Invention
The present invention relates to a substrate processing system.
Priority claimed on Japanese Patent Application No. 2009-160042, filed on Jul. 6, 2009, and Japanese Patent Application No. 2010-140954, filed on Jun. 21, 2010, the contents of which are incorporated herein by reference.
2. Description of the Related Art
For example, in a substrate processing system coating a thin film such as a resist film on various substrates such as a semiconductor substrate, a glass substrate forming a liquid crystal panel, and a substrate forming a hard disk, a coating device is used to form the coating film on the substrate while the substrate is rotated. In the coating device, in general, the substrate is laid down so as to be parallel to a horizontal plane and the substrate is rotated while the lower substrate surface is held.
Meanwhile, in the substrate used to form the hard disk, for example, it is necessary to coat the liquid material on both surfaces thereof. In the case of this kind of substrate in which both surfaces are required to be coated with the liquid material, it is not possible to hold the lower substrate surface. For this reason, Patent Reference 1, for example, discloses a technology in which the substrate is rotated while the substrate is held by a holding piece.
In the case where the liquid material is coated on both surfaces of the substrate when the substrate is laid down, the coating conditions between the top and bottom surfaces of the substrate are different. For this reason, the state of the thin film formed on the top surface of the substrate may be different from the state of the thin film formed on the bottom surface thereof. To the contrary, there has recently been proposed a technology in which the liquid material is simultaneously coated on both surfaces of the substrate in an upright (i.e. vertical) state.
In the case where the liquid material is coated on both surfaces of the substrate in an upright state, for example, a technique that a substrate is accommodated in an upright cup, and a liquid material is ejected from nozzles while rotating the substrate may be used. In this case, droplets of the liquid material are adhered to the inside of the cup, and the droplets may be adhered to the substrate as well. For this reason, it is necessary to appropriately clean the inside of the cup.
As a technique of cleaning the inside of the cup, for example, a technique that a dummy substrate of a size nearly equal to a substrate is disposed at a coating position for the substrate, and a cleaning liquid is ejected onto the dummy substrate by nozzles for cleaning may be used. In this case, droplets of the cleaning liquid ejected onto the dummy substrate are splashed inside the cup, and the cleaning liquid is supplied to the inside of the cup, which makes it possible to clean the inside of the cup with the cleaning liquid.
[Patent Reference 1]    Japanese Unexamined Patent Application, First Publication No. Hei 7-130642